CFD Study of Sensitivity Parameters in SCR NOx Reduction Modeling

Sampath, Manoj Kumar; Lacin, Figen

doi:10.4271/2014-01-2346

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…The volume percentage of NH 3 at the catalyst's output rises at first and then falls sharply. Due to the breakdown of the UWS and the reducing agent's reduction reaction increase with increasing exhaust temperature, there is a trade-off relationship between NH 3 generation and consumption [21,102]. In this work, we built a urea-SCR model based on an experiment, and we investigated the major elements that impact the system's performance.…”

Section: Diesel Engine 3900 CCmentioning

confidence: 99%

“…Several inengine technologies, including intercooling, turbocharging, injection rate shaping, injection pressure, injection time, development of smart controllers, and exhaust gas recirculation (EGR) have been employed to comply with legal requirements [19,20]. While some of these technologies are still in the development stage, others, such as homogeneous charge compression ignition (HCCI), suggest that future legislation will call for an aftertreatment system to reduce NOx and PM emissions to the necessary levels [21,22]. Among the factors included are restrictions placed on the combustion process, or research costs.…”

Section: Introductionmentioning

confidence: 99%

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Review of Improving the NOx Conversion Efficiency in Various Diesel Engines fitted with SCR System Technology

Wardana

2022

Catalysts

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The diesel engine is utilized in most commercial vehicles to carry items from various firms; nevertheless, diesel engines emit massive amounts of nitrogen oxides (NOx) which are harmful to human health. A typical approach for reducing NOx emissions from diesel engines is the selective catalytic reduction (SCR) system; however, several reasons make reducing NOx emissions a challenge: urea particles frequently become solid in the injector and difficult to disseminate across the system; the injector frequently struggles to spray the smaller particles of urea; the larger urea particles from the injector readily cling to the system; it is also difficult to evaporate urea droplets because of the exhaust and wall temperatures (Tw), resulting in an increase in solid deposits in the system, uncontrolled ammonia water solution injection, and NOx emissions problems. The light-duty diesel engine (LDD), medium-duty diesel engine (MDD), heavy-duty diesel engine (HDD), and marine diesel engine use different treatments to optimize NOx conversion efficiency in the SCR system. This review analyzes several studies in the literature which aim to increase NOx conversion in different diesel engine types. The approach and methods demonstrated in this study provide a suitable starting point for future research into reducing NOx emissions from diesel engines, particularly for engines with comparable specifications.

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Section: Diesel Engine 3900 CCmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Review of Improving the NOx Conversion Efficiency in Various Diesel Engines fitted with SCR System Technology

Wardana

2022

Catalysts

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“…Moreover, the presence of external heat losses can result in temperature variations across the monolith. According to Sampath and Lacin, temperature had the most significant impact on NO x conversion efficiency among all other parameters examined. Therefore, the effect of thermal variations on SCR performance would require careful analysis.…”

Section: Introductionmentioning

confidence: 98%

“…Urea–SCR systems offer good fuel economy and high NO x reduction efficiency, while being economically viable options for both light-duty and heavy-duty vehicles . While the urea–SCR devices offer benefits, current challenges toward system performance include urea conversion, NH 3 mixing and uniformity of NH 3 concentrations, urea deposit formation, catalyst selection for NO x reduction, etc. − …”

Section: Introductionmentioning

confidence: 99%

Modeling the Effect of Nonuniformities from Urea Injection on SCR Performance Using CFD

Dammalapati

Aghalayam

Kaisare

2019

Ind. Eng. Chem. Res.

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A computational fluid dynamics model, consisting of a mixing chamber coupled with a catalytic converter, is developed for the selective catalytic reduction (SCR) of NO x using urea. The NH3 required for the SCR reactions is produced from the injection and decomposition of urea in the mixing chamber. The conversion efficiency and concentration distribution of NH3 from the mixing chamber are analyzed for a range of operating conditions. The flow and species distribution profiles from the mixing chamber are incorporated as inlet boundary conditions at the entrance of the downstream SCR convertor. The SCR convertor comprises a central catalytic monolith and inlet and outlet diffuser sections. Variations in NO x concentration were observed within the monolith due to heat losses and nonuniformities in ammonia concentrations. While heat effects under non-isothermal conditions slightly improved the NO x conversion efficiency, nonuniformities in ammonia concentrations did not significantly influence the SCR performance. Thus, the radial variations in NH3 concentrations, owing to nonuniformity at the outlet of the mixing chamber, did not considerably impact the overall performance of the SCR. The effects of temperature, NO:NO2 ratio, and inlet velocity were investigated.

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“…VI emission regulations require a NO x conversion efficiency of between 90 and 95% [5]. The main factors affecting the NO x conversion efficiency of the SCR system are the temperature of the catalyst [6] and the space velocity [7,8], and the high-efficiency temperature window corresponding to different catalysts is also different [9]. Due to the limitations of the system's structure and cost, the temperature and gas hourly space velocity (GHSV) inside the mobile SCR catalyst after offline measurement cannot be directly measured [10].…”

Section: Introductionmentioning

confidence: 99%

Research on Mobile Machinery NOx Emission Control Based on a Physical Model and Closed-Loop Control

Yue

Zhang

et al. 2022

Processes

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Mobile machinery means a power-driven vehicle that is specifically designed and constructed to perform work on or off the road. To reduce the nitrogen oxide (NOx) emissions that come from mobile machinery, a combination of a physical model and closed-loop control is applied to the selective catalytic reduction (SCR) system. Based on the design of the variable cross-section extended exhaust structure, the differential pressure measurement was achieved, and the physical model of the exhaust flow based on the differential pressure was established. Based on the analysis of the heat and mass transfer process of the SCR catalyst, a prediction model for the internal temperature field of the catalyst was established by combining the upstream and downstream exhaust temperature sensors. Using the SCR downstream nitrogen oxides signal and the proportional–integral–derivative (PID) closed-loop control algorithm, segmented PID closed-loop control under the large hysteresis response of the SCR system was realized. The above algorithms were used to form the control code through MATLAB/Simulink and downloaded to the embedded microprocessor. The test results show that the established model can realize the real-time calculation of the exhaust gas flow rate and the internal temperature of the catalyst. Under steady-state conditions, the calculation error of the exhaust flow rate is less than ±3%, and the calculation error of the catalyst temperature is less than ±5%. Under transient conditions, the calculation error of the exhaust flow rate is less than ±9%, and the calculation error of the catalyst temperature is less than ±8%. The nitrogen–oxygen signal-based PID closed-loop algorithm can improve the nitrogen–oxygen conversion efficiency and control accuracy of the model.

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CFD Study of Sensitivity Parameters in SCR NOx Reduction Modeling

Cited by 9 publications

References 11 publications

Review of Improving the NOx Conversion Efficiency in Various Diesel Engines fitted with SCR System Technology

Review of Improving the NOx Conversion Efficiency in Various Diesel Engines fitted with SCR System Technology

Modeling the Effect of Nonuniformities from Urea Injection on SCR Performance Using CFD

Research on Mobile Machinery NOx Emission Control Based on a Physical Model and Closed-Loop Control

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